Self‐Supported Asymmetric Ce─O─Ni Sites Reconstructed From Biscuit‐Like MOFs for Efficient Urea Oxidation and Zn‐Urea Battery Applications
Liu Deng, Xingyu Guo, Tao Yang, Aiguo Kong, Dong Lv, Yang Yang, Xiangzhi Cui, Rui Liu
Abstract
Abstract Designing asymmetric active sites with tailored electronic structures is crucial for improving the sluggish kinetics of the urea oxidation reaction (UOR) in energy conversion systems. Herein, a unique biscuit‐like Ce‐doped Ni‐MOF (Ce─Ni─BDC) directly grown on nickel foam is synthesized through solvothermal coordination and ion exchange. The self‐supported electrode achieves exceptional UOR activity, requiring only 1.408 V (vs reversible hydrogen electrode (RHE), V RHE ) at 100 mA cm −2 , outperforming undoped Ni‐BDC, RuO 2 , and Pt/C benchmarks. When applied in a time‐decoupled Zn‐Urea battery, the system delivers a peak power density of 2.32 mW cm −2 along with hydrogen production. Operando studies reveal that asymmetric Ce─O─Ni sites facilitate reconstruction into Ce‐γ‐NiOOH at potentials 150 mV lower than conventional γ‐NiOOH formation, and the density functional theory calculations demonstrate that Ce 3d ‐O‐Ni 2p orbital hybridization evaluates d‐band center to −1.359 eV, which stabilizes the *CO intermediate while reducing the energy barrier for *COOH formation by 0.27 eV. This work provides a facile MOF‐derived route to engineer asymmetric metal sites, mechanistic insights into reconstruction dynamics and orbital interactions, and a practical demonstration in renewable energy storage systems.